1. Field of the Invention
The present invention relates to a method for inspecting a defect in a photomask for manufacturing a semiconductor device, a method for manufacturing a semiconductor device and a method for producing a photomask.
2. Description of the Related Art
An EB graphic drawing apparatus using an electron beam and a photo-repeater using a laser beam are known as apparatuses for drawing a pattern on a photomask. The photo-repeater is an apparatus in which an exposure apparatus for use in forming a pattern on a wafer is used to transfer a pattern on a photomask. The photo-repeater makes it possible to obtain a photomask having high dimension-uniformity.
Since the photo-repeater uses a laser beam such as an I beam, a KrF beam or an ArF beam, a photo-proximity effect arises when a pattern is drawn. Due to the photo-proximity effect, a line width, a corner shape and a line portion end shape of a pattern of a photomask cannot conform to those of the pattern of design data. However, as regards the line width of a pattern, the photomask can almost conform to the design data by means of known simulation using optical parameters and correction to the design data (photo-proximity effect correction).
A method of comparing a produced photomask with the design data for producing the photomask is known as a method for inspecting a photomask. FIG. 17 shows a conventional inspection method. As shown in FIG. 17, mask data 12 based on design data 11 is subjected to correction in accordance with a process conversion difference, so that graphic data 13 is produced. The process conversion difference means a correction value determined depending on a difference in shape between the mask data 12 and the produced photomask, which occurs in the process of producing the mask. When the process conversion difference is determined, the photo-proximity effect and the difference that occurs in etching or the like are taken into consideration.
Then, a photomask 14 is produced in accordance with the graphic data 13 by means of an EB graphic drawing apparatus, a photo-repeater or the like. The photomask 14 is compared with inspection data 15, so that whether the photomask 14 is defective or not is determined. The inspection data 15 is the same in shape as the mask data 12.